In recent years, as a result of widespread use of hybrid cars and the like, electric wires and connectors, which are automobile parts, are required to have high voltage resistance and high heat resistance. Conventionally, electric wires coated with a cross-linked vinyl chloride resin or electric wires coated with a cross-linked polyolefin have been used as insulated electric wires, such as wire harnesses for automobiles, to be used at positions with high temperatures. An electron beam cross-linking method is mainly used to perform cross-linking in these insulated electric wires (see Patent Document 1 JP2000-294039A, for example).
However, there is a problem in that an expensive electron beam cross-linking apparatus or the like is required to perform electron beam cross-linking, and equipment cost increases, resulting in increased product cost. Therefore, silane cross-linking that can be performed with inexpensive equipment has been attracting attention. Polyolefin compositions in which silane cross-linking can be performed and that are to be used in coating materials for electric wires, cables, and the like are known (see Patent Document 2 JP2000-212291A, for example).